Drinking water or potable water must be of a sufficiently high quality such that consumption of the water does not pose serious risks. One type of contaminant often found in groundwater is perchlorate salts. Perchlorate salts are generated as a by-product from rocket fuels and other explosives. Some perchlorate salts also occur naturally in the environment. Over time, the perchlorate salts each into the groundwater supply. Perchlorate salts dissolve into a cation and a corresponding perchlorate anion, ClO4−, which is particularly toxic to humans. Several reports suggest that ingestion of ClO4− inhibits normal function of the thyroid gland and contributes to hormonal imbalances. Recently, the U.S. Environmental Protection Agency (EPA) determined that ClO4− must be regulated as a water contaminant under the Safe Drinking Water Act (SDWA). Further, several states have independently enacted drinking water standards for ClO4−. Accordingly, there is considerable interest in effectively and efficiently removing ClO4− from drinking and potable water sources.
One method of removing ClO4− from drinking and potable water sources is through selective ion exchange. In this process, the water is directed through a strong base anion exchange resin and the ClO4− in the water binds to the resin. Over time, the resin becomes saturated with ClO4− and the resin needs to be regenerated. Because the ClO4− binds very tightly to the strong base anion resin, a solution having an extremely high salt concentration, typically between 7-12%, is required to remove the ClO4− from the resin. Further, it is difficult to dispose of the brine recovered from regenerating the resin because it is highly concentrated in ClO4−. Current methods for disposing of the brine include deep well injection. Accordingly, there is a need for an improved method of removing ClO4− from water, including brines recovered from resin regeneration, having a high concentration of ClO4−.